(a) Field of the Invention
The present invention relates to a three-dimensional (“3D”) image display device having a reverse phase lens structure.
(b) Description of the Related Art
Fast communication services based on the information superhighway are expected to evolve from simpler audio-based services, such as a current telephone service, to audible and visual multimedia services utilizing digital terminals processing characters, voices, and images quickly. Such services are eventually expected to be applied to 3D communication services that enable realistic and stereoscopic viewing and hearing, overcoming temporal and spatial limitations.
Typically, a 3D image is expressed by a principle of stereo vision of two eyes. Binocular disparity (e.g., a disparity images perceived by each of two eyes caused because they are separated apart by a distance of about 65 mm) plays an important role in a stereoscopic effect. That is, when left and right eyes view a 3D reality, each eye individually generates different 2D images and the two images are transmitted to the brain, the brain combines the two images to perceive depth in the original 3D reality. Such an ability is usually called stereography.
3D image display schemes using the binocular disparity are typically categorized, depending on a necessity for spectacles, as stereoscopic schemes such as a polarization scheme and a time divisional scheme, and autostereoscopic schemes such as a parallax barrier scheme and a lenticular scheme.
According to the stereoscopic schemes, a mass of people may simultaneously enjoy 3D images from all viewing angles if the polarization spectacles or liquid crystal shutter spectacles are worn. However, due to a drawback that the polarization spectacles or liquid crystal shutter spectacles must be worn, the stereoscopic schemes are not commonly used, and the stereoscopic schemes are typically limited to use in movie theatres.
In contrast, according to the various autostereoscopic schemes, there is a merit that additional spectacles are not required when enjoying the stereoscopic image.
Recently, according to the demands of the large scale and the reduction of thickness of display devices, techniques for reducing the weight and thickness of the display devices are required. Also, if the viewing angle is increased, the 3D visible region where the stereoscopic image can be shown is limited by increasing confusion between images viewed at each position within the viewing angle such that it is necessary to expand the 3D visible region through the wide viewing angle.